FATIGUE BEHAVIOUR OF WELDED JOINTS IN OFFSHORE STRUCTURES.

FATIGUE BEHAVIOUR OF WELDED JOINTS IN OFFSHORE STRUCTURES.

From 1985-01-01
to 1988-06-30

Project details

Total cost:

Not available

EU contribution:

Not available

Coordinated in:

Netherlands

Objective

IN ORDER TO WITHSTAND THE COMPETITION OF OTHER MATERIALS, NEW DESIGNS ARE PRESENTED WHICH AVOID THE NEED TO USE COMPLICATED AND EXPENSIVE NODES. INSTEAD OF THE TRADITIONAL TRUSS STRUCTURE A VERTICAL CYLINDER WITH A LARGE DIAMETER AND WALL THICKNESS WILL BE USED. HOWEVER THE FATIGUE BEHAVIOUR OF THESE THICK PLATES HAS NOT YET BEEN INVESTIGATED.

AN ON-GOING REVIEW OF THE REQUIREMENTS OF THE CODES IS EXTREMELY IMPORTANT. IN THIS CONNECTION IT IS ADVISABLE TO INVESTIGATE THE EFFECT OF A ROOT DEFECT ON FATIGUE BEHAVIOUR, BECAUSE THESE DEFECTS ARE ALMOST UNAVOIDABLE IN ONE-SIDE WELDING AND THERE IS SOME DOUBT WHETHER ALL ROOT DEFECTS NEED TO BE REPAIRED. BY AVOIDING THE NEED TO REPAIR THE WELDS MUCH TIME AND/OR MONEY CAN BE SAVED.

THE PROPOSED RESEARCH PROGRAMME DEALS WITH THE FOLLOWING ITEMS: - FATIGUE BEHAVIOUR OF WELDED STEEL JOINTS IN OFFSHORE STRUCTURES. THE FATIGUE BEHAVIOUR OF 1. A BUTT-WELDED THICK PLATE 2. A THICK PLATE WITH AN ATTACHMENT PERPENDICULAR TO THE MAIN STRESS DIRECTION 3. A THICK PLATE WITH AN ATTACHMENT PARALLEL WITH THE MAIN STRESS DIRECTION 4. ROOT DEFECTS IN A BUTT-WELDED TUBULAR CONNECTION

- FATIGUE LIFE ESTIMATION BASED ON A FRACTURE MECHANICS APPROACH ESPECIALLY FOR THE REGION OF LONGER FATIGUE LIVES.